栽培大豆(G.max)×半野生大豆(G.gracilis)后代主要农艺性状遗传参数的初步分析

A Preliminary Analisis on Genetic Parameters of Major Agronomic Characters of Progenies from Crosses between Cultivated (G.max) and Semi-wild Soybean (G.gracilis)

本试验利用三个不同结荚习性的栽培大豆(G.max)做母本,分别与三个半野生大豆(G.graeilis)按NCⅡ设计配制的9个杂交组合,估测了F_1、F_2代主要农艺性状的优势指数;F_2代主要农艺性状的平均数、变幅、遗传变异系数、遗传力和预期遗传进度。试验结果表明:F_1代除百粒重、主茎有效节数以外,其余性状均有明显的杂种优势;F_2代除有效分枝、主茎粗以外,其余性状的优势指数均明显下降;F_2代遗传变异幅度大小的趋势为有限组合>亚有限组合>无限组合;生育日数、株高的遗传力高,可在早期世代进行选择;单株粒数、单株荚数、主茎粗的遗传力低,应在较晚世代选择;单株粒重及其主要构成因素均有较大的遗传进度绝对值,无限组合的遗传进度明显低于有限、亚有限组合。

Progenies from 9 crosses between three cultivated soybean (G.max) of different terminaltypes and three semi--wild soybean (G.gracilis) were used to study the heterosis indices of ma-jor agronomic characters in F_1 and F_2 generations, and to investigate the means, ranges,GCV. s, heritabilities and genetic advances of these characters in F_2 generation. The resultsshowed that heterosis indices was the highest in seed yield per plant in F_1 generation.Numberof nods on main stem and 100 seed weight in F_1 were smaller than that of mid--parents. Ex-cept number of actual branches and diameter of main stem, the heterosis indices of all othercharacters. decreased in F_2 generation. Except 100 seed weight and number of nods on mainstem,some transgressive segregates over larger parents were found for all other characters inF_2 generation. Plants with seed weight larger than that of the bigger seed parents were sepa-rated from all crosses tested. Plants of 110 cm in height,350 pods per plant and erect mainstem were separated from determinate and semi--determinate crosses. The major charactersstudied had relative larger ranges of genetic variation in F_2 generation. Determinate andsemi--determinate crosses usually had larger ranges of variation than indeterminate crosses.High heritabilities were found for growing period and plant height, therefore, selections onsuch characters would be effective in early generations. Low heritabilities were found onnumber of seeds per plant, number of pods per plant and main stem diameter and selectionson such characters should be performed in later generations. High expected genetic advanceswere found in seed yeild, number of pods, and number of seed per plant,and 100 seed weight.In general, determinate and semi--determinate crosses had larger expected genetic advancesthan indeterminate crosses for most characters studied.